Sinusoidal Capillarization Research Articles

Focal Nodular Hyperplasia-Like Nodule with Reduced Expression of Organic Anion Transporter 1B3 in Alcoholic Liver Cirrhosis

We report a patient with alcoholic liver cirrhosis who had a 15 mm focal nodular hyperplasia (FNH)-like nodule in the liver. This FNH-like nodule was diagnosed as hepatocellular carcinoma (HCC) mainly based on hypervascularity during the hepatic arterial phase, washout pattern during the equilibrium phase and low signal intensity during the hepatobiliary phase in gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI; it was surgically resected. Its histology exhibited hepatocyte hyperplasia, fibrous septa containing unpaired small arteries accompanied by reactive bile ductules, remarkable iron deposits and sinusoidal capillarization, and was compatible with the diagnosis of an FNH-like nodule. When we analyzed the images of the present nodule retrospectively, low signal intensity on in-phase and isosignal intensity on opposed-phase T1-weighted MRI may have reflected iron deposits in the FNH-like nodule. In addition, a low signal intensity on T2-weighted MRI and no detection in diffusion-weighted MRI may help in distinguishing FNH-like nodules from HCC, since these image findings are inconsistent with typical HCC. Immunohistochemical analysis revealed a markedly reduced expression of organic anion transporter (OATP) 1B3 in this nodule, which implied decreased Gd-EOB-DTPA uptake by hepatocytes and accounted for the low signal intensity during the hepatobiliary phase on Gd-EOB-DTPA-enhanced MRI. To the best of our knowledge this is the first report in which an FNH-like nodule was assessed for OATP1B3 expression.

No contribution of umbilical cord mesenchymal stromal cells to capillarization and venularization of hepatic sinusoids accompanied by hepatic differentiation in carbon tetrachloride-induced mouse liver fibrosis

The acceleration of capillarization and venularization of hepatic sinusoids after cell therapy would not be beneficial to restoration after liver disease. The goal was to observe the effects of umbilical cord (UC)-derived mesenchymal stromal cells (MSC) on liver microcirculation and their therapeutic potential in liver fibrosis. Human UC MSC labeled with or without CM-DIL were transplanted into NOD/SCID mice with carbon tetrachloride (CCl4)-induced chronic liver fibrosis models. Because of the high autofluorescence on the injured liver sections, we used immunohistochemistry, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR), but not immunofluorescence, in order to avoid false images under a confocal fluorescence microscope. Human-specific alpha-fetoprotein and albumin mRNA and proteins were detected in CCl4-treated mouse livers receiving human UC MSC transplants. We only observed the gene expression of human-specific endothelial-like cells markers CD31 and KDR by RT-PCR, but not protein expression by immunohistochemistry, in UC MSC-transplanted mouse livers. Vascular endothelial growth factor (VEGF) expression in injured livers 4 weeks after UC MSC transplantation was higher than in normal livers. However, UC MSC injection did not increase significantly the vascular density labeled by CD31 and (vWF) in the injured livers of UC MSC-transplanted mice compared with non-transplanted mice after CCl4 treatment. In addition, liver function was partly improved after UC MSC transplantation. Human UC MSC can differentiate into hepatocyte-like cells but do not accelerate the capillarization and venularization of hepatic sinusoids, finally leading to the partial improvement of liver function in mice with CCl4-mediated chronic liver fibrosis.

Expression of CD34 in cirrhotic liver: Reliance to dedifferentiation

The vascular supply of dysplastic nodules (DN) is altered compared with surrounding cirrhotic nodules. Dysplastic nodules contain unpaired arteries which are isolated arteries unaccompained by bille ducts. In adition, capillarization or neovascularization is evident on CD34 and CD31 staining. The investigation of angiogenic profile of regenerative, dysplastic and nodules of hepatocellular carcinoma aimed at assessing whether vascular profile is in reliance to the process of dedifferentiation of hepatocytes during the course of cirrhosis. Thirty four liver nodules from surgical biopsies of 12 patients previously undiagnosed to have cirrhosis, were classified as regenerative, dysplastic and small hepatocellular carcinomas (HCC). The investigation included 8 large regenerative nodules (LRN), 11 low grade dysplastic nodules (LGDN), 12 high grade dysplastic nodules (HGDN) and 3 early HCC. Serial sections of the nodules and surrounding cirrhotic liver tissue were immunostained against CD34. The vascular counting method was performed. The results were analysed using SPSS computer statistical program. The number of capillary unites showed significant differences among nodular types, with the largest number of capillaries in hepatocellular carcinoma as well as strong reliance to dedifferentiation. There is a significant correlation of sinusoidal capillarization to dediferentiation of the liver tissue during the course of cirrhosis. From diagnostic view, capillary counting may be helpful to distinguish dysplastic from nondysplastic nodules. The appearance of dysplastic nodules in nonselected surgical biopsies is frequent enough to challenge caution during the follow-up of cirrhotic patients.

Vascular Immunohistochemical Markers: Contributions to Hepatocellular Nodule Diagnosis in Explanted Livers

Introduction The process of hepatic carcinogenesis involves a progression including large regenerative nodules, to dysplastic nodules, and finally to hepatocellular carcinoma. Angiogenesis is fundamental to the development of malignant tumors. Changes in sinusoidal capillarization and isolated arteries occur early in hepatic carcinogenesis. However, sometimes differentiation of hepatocellular nodules can be difficult for the general pathologist. The aim of this study was to evaluate angiogenesis by immunohistochemistry using CD34 and HHF35 antibodies for differential diagnosis of large regenerative nodules versus dysplastic nodules versus hepatocellular carcinoma using explanted cirrhotic livers. Methods Seventy-nine nodules obtained from 29 explanted cirrhotic livers were classified according to the International Working Party as follows: 17 large regenerative, 23 low-grade dysplastic, 23 high-grade dysplastic, and 16 hepatocellular carcinomas. These nodules were submitted to immunohistochemistry with antibodies to CD34 and HHF35 to analyze sinusoidal capillarization and arterialization, respectively. Results Semiquantitative analysis revealed that CD34 expression was >30% in dysplastic nodules and hepatocellular carcinoma; the staining in 93.8% of cases was diffuse, almost involving the entire sinusoidal lining in hepatocellular carcinoma. The number of isolated arteries was high in hepatocellular carcinoma (average, 4.369), which positively correlated with the other nodules ( P < .005). Conclusion Quantification of sinusoidal capillarization and isolated arteries in hepatocellular nodules, as detected with CD34 and HHF35 antibodies, respectively provided an important tool to differentiate dysplastic nodules from hepatocellular carcinoma.

Expression of LYVE-1 in sinusoidal endothelium is reduced in chronically inflamed human livers

LYVE-1, a specific marker of lymphatics, is expressed in hepatic sinusoidal endothelium. A previous study revealed that LYVE-1 expression in sinusoidal endothelium was reduced in cirrhosis. However, it is still obscure how LYVE-1 expression in sinusoidal endothelium was reduced during the disease progression. To elucidate whether there were relationships among LYVE-1 attenuation, sinusoidal capillarization, and disease progression, we performed immunohistochemical investigations based on frozen human livers. Frozen liver sections of chronic hepatitis (n = 8), cirrhosis (n = 13), and normal/control liver (n = 10) were examined by immunostaining for lymphatic endothelial markers (LYVE-1 and D2-40) and vascular endothelial markers (CD31 and von Willebrand factor). Computer-aided morphometry was applied to obtain objective data. The diseased liver tissues were also examined ultrastructurally. In controls, sinusoidal endothelium was positive for LYVE-1 and CD31, but negative for D2-40 and von Willebrand factor. In chronic hepatitis and cirrhosis, LYVE-1 expression in sinusoidal endothelium was attenuated, especially in areas adjacent to active inflammatory or fibrotic lesions, while von Willebrand factor was reciprocally expressed in sinusoidal endothelium. The morphometric analyses revealed that LYVE-1 positivity in sinusoidal endothelium was significantly (P < 0.0001) decreased in chronic hepatitis and cirrhosis compared to controls and was negatively correlated (Rs = -0.72, P < 0.0001) to von Willebrand factor positivity. Furthermore, LYVE-1 positivity was negatively correlated to inflammatory grade (Rs = -0.51, P = 0.021) and fibrosis severity (Rs = -0.46, P = 0.038). Sinusoidal endothelium in the diseased livers showing LYVE-1 attenuation had lost fenestrations. These findings indicated that LYVE-1 attenuation in sinusoidal endothelium was one of the manifestations of capillarization, and was associated with hepatic disease progression.

Relationship between cyclooxygenase-2 and vascular endothelial growth factor with liver sinusoidal capillarization of chronic hepatitis B

Objective To study the relationship between expression of cyclooxygenase-2 (COX-2) and vas-culax endothelial growth factor (VEGF) with liver sinusnidal capillarization (LSC) of chronic hepatitis B (CHB). Methods We studied liver biopsies from 200 patients with CHB COX-2 ,VEGF immunohistochemical stain were ob-served to accomplish relationship between expression of COX-2,VEGF and LSC. Results LSC occupy above 80% in the group. There were manifestation in mild-LSC (focal) , middle-LSC (sheet-shape) and severe-LSC (widespread). Electron microscope shown the laceration in the endothelium of sinuses and formation of basal lamina and budding for-mation lumen of blood vessel and fat-storing cell convert myofibroblast. Expression of COX-2, VEGF, Co-Ⅳ and retic-ulum, collagen and elastic fibers with mild or severe in LSC is manifest locking relate. Conclusion Increased ex-pression of COX-2 ,VEGF in liver tissue of CHB may facilitate LSC and hepatic fibrosis. Key words: Epoxide hydrolases; Angiogenesis inhibitors; Liver sinusoidal capillarization; Hepatitis B, chronic

Hepatocarcinogenesis: Multistep Changes of Drainage Vessels at CT during Arterial Portography and Hepatic Arteriography—Radiologic-Pathologic Correlation

To clarify the changes that occur in drainage vessels of dysplastic nodules and hepatocellular carcinoma (HCC) during hepatocarcinogenesis by using computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA), with histologic findings as the reference standard. Institutional ethics committee approval and informed consent were obtained. According to the findings at CTAP and CTHA, 46 surgically resected hepatocellular nodules were classified into three types: type A (n = 18) (equivalent or decreased portal perfusion compared with background liver at CTAP, decreased arterial perfusion, and no corona enhancement [perinodular contrast material drainage] at CTHA), type B (n = 13) (no portal perfusion, increased arterial perfusion, and thin (< or = 2-mm) corona enhancement), or type C (n = 15) (no portal perfusion, increased arterial perfusion, and thick (> 2-mm) corona enhancement). We compared the histopathologic features and microangioarchitecture between the types. Type A nodules histologically consisted of dysplastic nodules and well-differentiated HCC; type B and C nodules were moderately differentiated HCC. Replacing growth was commonly observed in type A nodules, whereas compressing growth was more frequently seen in types B and C. Sixty percent of type C nodules had a fibrous capsule. There were significantly fewer intranodular hepatic veins in types B and C. Serial pathologic slices demonstrated continuity from intranodular capillarized sinusoids to hepatic veins in type A nodules and to surrounding hepatic sinusoids in type B nodules. In type C nodules, intranodular capillarized sinusoids were connected to extranodular portal veins either directly or through portal venules within the fibrous capsule. Drainage vessels of HCC change from hepatic veins to hepatic sinusoids and then to portal veins during multistep hepatocarcinogenesis.

Pathogenesis of liver fibrosis in patients with chronic hepatitis B

To explore the role of sinusoidal endothelial cell in the development of liver fibrosis, and to dissect the relationship among hepatic microcirculation disorders, hepatic sinusoidal capilarization and liver fibrosis. Liver biopsy was performed in fifty-six patients with chronic hepatitis B. The liver tissues were observed under light microscope and transmitted electronic microscope. Of 56 cases, 39 cases were mild hepatitis, 10 were moderate hepatitis, and 7 were severe hepatitis. The morphology of hepatic stellate cells (HSCs) was similar to that of fibroblasts in the tissues of the patients with chronic hepatitis B. Collagenous fibers were deposited around the hepatic stellate cells. Electron-dense materials were deposited between sinusoidal endothelial cell and hepatic stellate cell. The size and amount of fenestraes of sinusoidal endothelial cells were reduced in 53 of 56 cases. The consecutive or inconsecutive membrane-like materials were observed along sinusoidal endothelial cells in 20 cases. Collagen fibers were observed in the space of Disse in 15 cases. Even in the patients with normal hepatic functions, red blood cells aggregation and microthrombi could be observed in the liver tissues. Sinusoidal endothelial cells are involved in development of liver fibrosis by interacting with hepatic stellate cells. Hepatic microcirculation disorders and sinusoidal capillarization are important changes in the early stage of liver fibrosis.

Arsenic Requires Sphingosine-1-Phosphate Type 1 Receptors to Induce Angiogenic Genes and Endothelial Cell Remodeling

Arsenic in drinking water is a major public health concern as it increases risk and incidence of cardiovascular disease and cancer. Arsenic exposure affects multiple vascular beds, promoting liver sinusoidal capillarization and portal hypertension, ischemic heart disease, peripheral vascular disease, and tumor angiogenesis. While Rac1-GTPase and NADPH oxidase activities are essential for arsenic-stimulated endothelial cell signaling for angiogenesis or liver sinusoid capillarization, the mechanism for initiating these effects is unknown. We found that arsenic-stimulated cell signaling and angiogenic gene expression in human microvascular endothelial cells were Pertussis toxin sensitive, indicating a G-protein coupled signaling pathway. Incubating human microvascular endothelial cells with the sphingosine-1-phosphate type 1 receptor (S1P(1)) inhibitor VPC23019 or performing small interfering RNA knockdown of S1P(1) blocked arsenic-stimulated HMVEC angiogenic gene expression and tube formation, but did not affect induction of either HMOX1 or IL8. Liver sinusoidal endothelial cells (LSECs) defenestrate and capillarize in response to aging and environmental oxidant stresses. We found that S1P(1) was enriched on LSECs in vivo and in primary cell culture and that VPC23019 inhibited both sphingosine-1-phosphate-stimulated and arsenic-stimulated LSEC oxidant generation and defenestration. These studies identified novel roles for S1P(1) in mediating arsenic stimulation of both angiogenesis and pathogenic LSEC capillarization, as well as demonstrating a role for S1P(1) in mediating environmental responses in the liver vasculature, providing possible mechanistic insight into arsenic-induced vascular pathogenesis and disease.

Arsenic requires sphingosine‐1‐phosphate type 1 receptors to induce angiogenic genes and endothelial cell remodeling

Arsenic increases risk and incidence of cardiovascular diseases and cancers. Arsenic affects multiple vascular beds to promote liver sinusoidal capillarization and portal hypertension, ischemic heart disease, peripheral vascular disease, and tumor angiogenesis. The mechanism for initiating arsenic signaling in endothelial calls is unknown. We found that arsenic‐stimulated cell signaling and angiogenic gene expression in human microvascular endothelial cells (HMVEC) were Pertussis toxin sensitive indicating a G‐protein coupled signaling pathway. Both the sphingosine‐1‐phosphate type 1 receptor (S1P1) inhibitor VPC23019 and siRNA knockdown of S1P1 blocked arsenic‐stimulated HMVEC angiogenic gene expression and tube formation, but not induction of HMOX1or IL8. S1P1 was enriched on liver sinusoidal endothelial cells (LSEC) in vivo and VPC23019 inhibited arsenic‐stimulated oxidant generation and capillarization. These studies identified novel roles for S1P1 in mediating arsenic stimulation of both angiogenesis and pathogenic LSEC capillarization, as well as demonstrated a novel role for S1P1 in mediating environmental responses in the liver vasculature. Thus, they provide possible mechanistic insight into arsenic‐promoted vascular pathogenesis and disease promotion.

Dynamic contrast-enhanced CT imaging of hepatocellular carcinoma in cirrhosis: feasibility of a prolonged dual-phase imaging protocol with tracer kinetics modeling

Dynamic contrast-enhanced (DCE) CT imaging of four patients with hepatocellular carcinoma (HCC) was performed using a dual-phase imaging protocol designed with initial rapid dynamic imaging to capture the initial increase in contrast medium enhancement in order to assess perfusion, followed by a delayed imaging phase with progressively longer intervals to monitor subsequent tissue enhancement behaviour in order to assess tissue permeability. The DCE CT images were analysed using a dual-input two-compartment distributed parameter model to yield separate estimates for blood flow and permeability, as well as fractional intravascular and extravascular volumes. The HCCs and surrounding cirrhotic liver tissues were found to exhibit enhancement curves that can be appropriately described by two distinct compartments separated by a semipermeable barrier. Early contrast arrival was also found for HCC as compared with background liver. These findings are consistent with the current understanding of sinusoidal capillarization and hepatocarcinogenesis.

Effect of Fuzheng Huayu formula and its actions against liver fibrosis.

Liver fibrosis is a common histological process to develop into cirrhosis in various chronic liver diseases including chronic hepatitis and fatty liver. Therefore anti-liver fibrosis is very important strategy to treat chronic liver diseases. Fuzheng Huayu (FZHY), a preparation containing herbs such as Radix Salvia Miltiorrhizae, Cordyceps, Semen Persicae, was formulated on the basis of Chinese medicine theory in treating liver fibrosis and was approved. Pharmacological studies and clinical trials demonstrate that FZHY has a significant effect against liver fibrosis and that many of the pharmacological actions are attributable to the effect. This article reviews the effects and actions of FZHY, in particular the effects observed from clinical trials in treating liver fibrosis caused by chronic hepatitis B and the actions on inhibition of hepatic stellate cell activation, protection of hepatocytes and inhibition of hepatic sinusoidal capillarization. This article also reviews the coordinated effects of the constituent herbs of FZHY and the actions of their active compounds such as salvianonic acid B (SA-B) on liver fibrosis.

Arsenic-stimulated liver sinusoidal capillarization in mice requires NADPH oxidase–generated superoxide

Environmental arsenic exposure, through drinking contaminated water, is a significant risk factor for developing vascular diseases and is associated with liver portal hypertension, vascular shunting, and portal fibrosis through unknown mechanisms. We found that the addition of low doses of arsenite to the drinking water of mice resulted in marked pathologic remodeling in liver sinusoidal endothelial cells (SECs), including SEC defenestration, capillarization, increased junctional PECAM-1 expression, protein nitration, and decreased liver clearance of modified albumin. Furthermore, the pathologic changes observed after in vivo exposure were recapitulated in isolated mouse SECs exposed to arsenic in culture. To investigate the role of NADPH oxidase-generated ROS in this remodeling, we examined the effect of arsenite in the drinking water of mice deficient for the p47 subunit of the NADPH oxidase and found that knockout mice were protected from arsenite-induced capillarization and protein nitration. Furthermore, ex vivo arsenic exposure increased SEC superoxide generation, and this effect was inhibited by addition of a Nox2 inhibitor and quenched by the cell-permeant superoxide scavenger. In addition, inhibiting either oxidant generation or Rac1-GTPase blocked ex vivo arsenic-stimulated SEC differentiation and dysfunction. Our data indicate that a Nox2-based oxidase is required for SEC capillarization and that it may play a central role in vessel remodeling following environmentally relevant arsenic exposures.

Thy-1 is expressed in myofibroblasts but not found in hepatic stellate cells following liver injury

Thy-1 (CD90) is an adhesion molecule induced in fibroblast populations associated with wound healing and fibrosis. In this study the question whether Thy-1-gene-expression can be induced in hepatic stellate cells (HSC) in vivo, under conditions of liver injury or liver regeneration was addressed. Acute and chronic rat liver injury was induced by the administration of CCl4. For comparison, cirrhotic human liver, and rat 67% partial hepatectomy (PH) was studied as well. Thy-1-gene-expression was examined also in isolated human liver myofibroblasts. Thy-1-mRNA expression was significantly upregulated in chronic liver injury. Thy-1+ cells were detected in the periportal area of rat liver specimens in normal-, injured- and regenerative-conditions. In chronic human and rat liver injury, Thy-1+ cells were located predominantly in scar tissue. In the pericentral necrotic zone after CCl4-treatment, no induction of Thy-1 was found. Gremlin and Thy-1 showed comparable localization in the periportal areas. Thy-1 was not detected in either normal or capillarized sinusoids, in isolated rat HSC, and was neither inducible by inflammatory cytokines in isolated HSC, nor upregulated in treated myofibroblasts. Based upon these data Thy-1 is not a marker of "activated" sinusoidal HSC, but it is a marker of "activated" (myo)fibroblasts found in portal areas and in scar tissue.

The angiogenic makeup of human hepatocellular carcinoma does not favor vascular endothelial growth factor/angiopoietin-driven sprouting neovascularization

Quantitative data on the expression of multiple factors that control angiogenesis in hepatocellular carcinoma (HCC) are limited. A better understanding of the mechanisms underlying angiogenesis in HCC will improve the rational choice of anti-angiogenic treatment. We quantified gene and protein expression of members of the vascular endothelial growth factor (VEGF) and angiopoietin systems and studied localization of VEGF, its receptors VEGFR-1 and VEGFR-2, Angiopoietin (Ang)-1 and Ang-2, and their receptor, in HCC in noncirrhotic and cirrhotic livers. We employed real-time reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunohistology, and compared the outcome with highly angiogenic human renal cell carcinoma (RCC). HCC in noncirrhotic and cirrhotic livers expressed VEGF and its receptors to a similar extent as normal liver, although in cirrhotic background, VEGFR-2 levels in both tumor and adjacent tissue were decreased. Ang-1 expression was slightly increased compared with normal liver, whereas Tie-2 was strongly down-regulated in the tumor vasculature. Ang-2 messenger RNA (mRNA) levels were also low in HCCs of both noncirrhotic and cirrhotic livers, implying that VEGF-driven angiogenic sprouting accompanied by angiopoietin-driven vascular destabilization is not pronounced. In RCC, VEGF-A levels were one order of magnitude higher. At the same time, endothelially expressed Ang-2 was over 30-fold increased compared with expression in normal kidney, whereas Ang-1 expression was decreased. In hepatocellular carcinoma, tumor vascularization is not per se VEGF/angiopoietin driven. However, increased CD31 expression and morphological changes representative of sinusoidal capillarization in tumor vasculature indicate that vascular remodeling is taking place. This portends that therapeutic intervention of HCC at the level of the vasculature is optional, and that further studies into the molecular control thereof are warranted.

Vascular Changes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most vascular solid tumors, in which angiogenesis plays an important role. The status of angiogenesis in HCC correlates with the disease progression and prognosis, and thus provides a potential therapeutic target. This review summarizes the vascular changes and molecular and cellular basis of angiogenesis in HCC. Development of HCC is characterized by arterialization of its blood supply and sinusoidal capillarization. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that plays a critical role in mediating angiogenesis in HCC. The VEGF can function on various types of cells, such as endothelial cells, hepatic stellate cells, endothelial progenitor cells and hemangiocytes, to induce vascular changes in HCC. Therefore, blockade of VEGF-mediated pathways, either by anti-VEGF neutralizing antibody or tyrosine kinase inhibitors that target VEGF receptors, suppresses carcinogenesis and angiogenesis in HCC. In addition to VEGF, several other angiogenic factors in HCC have recently been identified. These factors can also regulate angiogenic processes through interaction with VEGF or VEGF-independent pathways. Despite the fact that treatment of HCC remains a tough task due to lack of effective systemic therapy, antiangiogenic therapy has already entered clinical trials in HCC patients and sheds light on a promising novel treatment for this disease.

A morphometric model to minimize subjectivity in the histological assessment of hepatocellular carcinoma and its precursors in cirrhosis

To explore how morphometry can minimize subjectivity in the assessment of liver nodules in cirrhosis using a novel classification tool. Ten hepatocellular carcinoma (HCC), 6 large regenerative nodules (LRN), and 34 regenerative (cirrhotic) nodules (RN), obtained from cirrhotic explant livers, were analyzed using a Kontron-Zeiss KS400 image analyzer. We generated a morphometric model based on the analysis of volume fractions occupied by hepatocyte nuclei/cytoplasm, sinusoidal endothelium and lumen, neoplastic acini, fibrosis, centrilobular veins, portal arteries, veins and bile ducts, individual lesional arteries (smooth muscle actin), and capillarized sinusoids (CD34), and on surface fraction occupied by reticulin, and number in unit volume and size distribution of hepatocyte nuclei, and mean hepatocyte nucleus diameter and volume. Volume fraction of capillarized sinusoids and of individual lesional arteries were more prominent in HCC and LRNs, when compared with RN, whereas surface fraction of reticulin was markedly decreased in HCC. The morphometric values of these three features were integrated into our classification tool to construct a hybrid system, which reclassified the nodules in the same categories. Our novel hybrid classification tool may minimize subjectivity in the histological assessment of nodular lesions in cirrhosis.

Ultrastructural changes in TAA induced hepatic cirrhosis in rats

Objective To observe the ultrastructural changes in liver after portal hypertension in rats.Methods A total of 50 rats were divided into the model groups(40)and control groups(10).The rats in the model group accepted 0.03% TAA administration.Five weeks later,the concentration of TAA was changed to 0.04% for induction for 10 weeks to establish the model of portal hypertension.The pressure of superior mesenteric vein was determined and cirrhotic liver samples obtained.The ultrastructuraI changes of were observed under electron microscope.Results The fenestra quantity of endothelial cells was significantly lower in the model group(P＜0.01).The portal vein pressure was markedly higher in the control group(P＜0.01).Conclusion Hepatic sinusoid capillarization plays an important role in occurrence of portal hypertension.The fenestra of endothelial cells in hepatic sinusoid reduces and the diameter of fenestra decreases.The formation of basement membrane impaires the substance exchange between blood and hepatic cells,which results in oxygen deficiency,metabolic product accumulation and cell necrosis. Key words: Liver cirrhosis; Portal hypertension; Fenestra; Endothelial cell; Electron microscope

Arsenic signals through g‐proteins and NADPH Oxidase (NOX) to promote mouse liver sinusoidal endothelial cell capillarization

Arsenic is a global health hazard that may cause disease in over 100 million people world‐wide. Liver disease including portal hypertension, non‐cirrhotic portal fibrosis, and vascular shunting and oxidative injury are associated drinking water with elevated arsenic levels. Liver sinusoidal endothelial cell (LSEC) capillarization with loss of fenestrations and increased surface expression of PECAM‐1 is an early event in these diseases. Drinking water containing 10 ppb or more of arsenic promotes LSEC capillarization in mice through unknown mechanisms. Therefore, the hypothesis that arsenic signals through NOX to promote LSEC capillarization was tested in primary mouse LSEC cultures. Ex Vivo arsenic exposures (0.5–5 μM) for 8 h recapitulated in vivo effects on capillarization. The ex vivo exposures increased superoxide generation that was prevented by pre‐incubating cells with the scavenger tempol or a selective NOX2 inhibitory peptide, gp91‐tat. Both tempol and gp91‐tat prevented arsenic‐stimulated capillarization. Finally, inhibition of either Gai or Rac1 GTPase also blocked arsenic‐stimulated oxidant generation and capillarization. These data are first demonstrating that environmental levels of arsenic stimulate LSEC capillarization through a g‐protein coupled, NOX‐mediated signaling cascade. Sponsored by EPA STAR grant FP‐91654201 and NIEHS grant R01ES013781.

Ginkgo Biloba Extract EGb 761 Alleviates Hepatic Fibrosis and Sinusoidal Microcirculation Disturbance in Patients with Chronic Hepatitis B.

BackgroundFew clinical data are available regarding the effect of Ginkgo biloba extract (EGb 761) on liver microcirculation and fibrosis. This randomized, controlled trial is to investigate the effect of Ginko biloba extract EGb 761 on liver fibrosis and hepatic microcirculation in patients with chronic hepatitis B.MethodsSixty-four patients with chronic hepatitis B were randomized for intention-to-treat. Thirty-two patients were assigned to treated group receiving EGb 761 plus polyunsaturated phosphatidylcholine (Essentiale), 32 patients received Essentiale as controls. Blood samples were taken for measurement of transforming growth factor beta-1 (TGF-β1), platelet activate factor (PAF), endothelin 1 (ET-1). Twenty-six patients in treated group and 21 patients in control group underwent liver biopsies for histology before and after treatment. Ultrastructural study for sinusoidal microcirculation before and after treatment was carried out on 10 randomly selected patients in each group.ResultsIn the treated group, after EGb 761 treatment, there was a significant reduction of blood TGF- β1, PAF and ET-1 (p<0.05), whereas this was not observed in the controls. After treatment in both groups, there were significant decrease of ALT, TBil and PT (p<0.05), and significant increase of ALB (p<0.05). Hepatic inflammation and fibrosis significantly alleviated in the treated group, but not in the controls. After EGb 761 treatment, electron microscopy showed red blood cell aggregates and microthrombosis disappeared or decreased in sinusoids; collagen deposits in sinusoidal lumen and Disse space reduced; sinusoidal capillarization alleviated.ConclusionsEGb 761 can improve sinusoidal microcirculation, alleviate inflammation and inhibit fibrosis through multiple mechanisms, it is effective in the treatment of chronic liver diseases.